Blading of fluid-pressure turbines



Patented May 26,

UNITED STATES nmz msm., or naomi, czacnosnovam emma or rLUm-rnnssnna transmits.

' l appunti@ mea ny 1s, 1924. smal nu. 713,843.

To all whom it may concern: Be it known that I, FRANZ LsnL, a citizen of Czechoslovakia, residing at lBrunn, Czechoslovakia, have invented certain new and useful Improvements in the Blading of Fluid-Pressure Turbines, of. which the following is a specification. u

My invention relates to the bladlng of elastic fiuid turbines, that is to say of gas or steam turbines. My invention includes the following features, namely the entering edges of the blades particularly in the last rows of the turbine are partl rounded and partly sharp'edged, and pre erably the enf tering edges and also if desired the escape edges of the blades are not in the shape of straight radial lines. Preferably that part of each entering .edge which is not in the shape ofl a straight radial line is rounded in transverse section whileY the remainder of the said edge is sharp edged.

In the annexed drawingf Fig. 1 is a view in longitudinal section through a part of the rotor and a part of the stator of an elastic fluid turbine, and shows a guide blade row and a rotor blade vrow in side elevation;

Figs. 2, 3 and 4 are views similar to Fig. 1, but showing by way of example, other constructional orms of improved blades;

Fig'.` 5 is aview showing in order from top to bottom sections of the blades shown in Fig. 1 .taken on the lines I-I, II-II and IIL-III, respectively; and 35 Figs. 6, 7 and 8 are views similar to Fig. 5, but showing sections of the blades in Figs. 2, 3 and 4 respectively.'

The stator blades secured in the turbine casing or to the stator carrier z are marked a, a2' and a, whilethe blades mounted/1n the rotor raremarked b, b, b, and 6,. The direction of the flow of the driving luid is indicated by the arrow A, d -denotes the inner diameter and D thelarger outer diameter ofthe blading.

As is seen in Figs. 1, 2, 3,'4 andthe sections therethrough in Figs. 5, 6, 7 and 8, the entering edges of all the constructional forms of my improved blades are partly rounded and partly sharp edged. The entering edges diifer from a radial straight line. In the blades a, a, and b, both the entering edges and the escape edges are curved, in the blades b, o2, b2 the escape edge is a radial straight line while part of the entering edge is a' strai ht radlal line and part thereof is curved. n the blade b1, the entering edge and in-the blade ar, both the entering edge and the escape edge are formed yby two straight lines at an obtuse angle to each other. It is to be understood that in all cases the edges of the blades are in planes substantially radial to the'rotor axis.

The entering edges of the blades and more particularly those parts of the same which are not formed by radial straight lines are rounded in transverse section as shown in the sections Figs. 5-8 while the remaining part of such edges may be sharp as usual. In order to avoid difficulties in mounting and dismounting, the escape edges of A"the stator blades will, in the majority of cases, be made straight or slightly curved. The spaces between vthe escape and entering edges of adjacent blades may beof the same width throughout or may vary in width as is seen in Figs. 1 to 4.

This improved blading is more particularly designed for the low pressure end of turbines and especially for their last rows in order tov reduce to a minimum the corrosions due to moisture and condensed water in the steam or elastic fluid and any injury to the edges of the blades, and in order to prevent the elastic fluid issuing lfrom one blade into the next from blowing and striking against the back of the blades on the entrance side when the load is reducedand the fluid velocities altered and thus by shaping the blades avoid the losses caused thereby and due toeddies, shocks and the like. When the load of a turbine is greatly reduced the velocity of the fluid in thespaces between the blades issuing from one .blade into the next is likewise notably reduced and.

acsI

The invention oiers the advantages that,

in shaping the blades according to the ine axial width of the/blades may thereby be altered incertain cases as is evident from Figs. 1, 2 and 3, and fromvtheir sections Figs. 5, 6 and 7 According to the increasedl shaping and rounding of the blades `outwardly and radially, the entrance edge angle of the blades also increases outwardly and radially, which is made evident by the angles a, al, a2; and indicated in Fig. 5. This is also evident from Figs. 6, 7 and 8 although the angles are not there in dicated. Shaping the blades according to the invention produces the best results and increases the turbine efliciency, reliability and performance, particularly at partial loads and in the low pressure or vacuum end of the turbine.

My invention permits such shaping of the blades and their edges that within Wide limits of variations of load and the alterations of the fluid velocities and directions due thereto all the working streams ofthe fluid are taken up by the front working faces of the blades and do not hit or strike their backs, and the blades, particularly at their entrance parts, are subject to wear and tear to a much less extent than heretofore;

It is a matter of course that all blades in the lowpressure end of a turbine or in a part therein, particularly inthe last rows, could be made in one of the shapes described, or in a plurality of shapes within the scope of this invention. But generally. only onev of the sha-pes is applied in a turbine.

What I claim is: Y Y

1. A blade for an elastic iiuid turbine having an entrance edge partly rounded and partly sharp.

2. In an elastic fluid turbine, a blade row comprising blades, each of which has anV entrance edge partly rounded and partly sharp. y

3. In an elastic iluid turbine, a blade row comprising blades, each of which has an entrance edge partly rounded and partly sharp, and a sharp escape edge.

4. In an elastic fluid turbine, a blade row comprising blades, each of which has an entrance edge partly roundedand partly sharp, the rounded part and the sharp part being di-sposed outwardly `and inwardly, respectively, radially of the turbine.

5. In an elastic fluid turbine, a blade row comprising blades each of which has an entrance edge sharp at one end and changlng gradually radially and outwardly of the turbine into a rounded edge part, having the I greatest rounding at the point farthest out along a radial line.

6. In an elastic fluid turbine, at least one v ing an entrance edge partly rounded and partly sharp.

7. In an elastic fluid turbine, at leastone rotor blade row comprising rotor blades and at least one guidin blade row, comprising guide blades, each ladeof both rows having an entrance edge partly rounded and partly sharp, and a sharp escape edge.l

8. In an elastic fluid turbine, at least one rotor blade row comprising rotor blades and at least one guidingblade row, comprising guide blades, each blade of both rows having an entrance edge partly rounded and partly shar the rounded part and the sharp part being isposed .outwardly and inwardly, respectively, radially of the turbine.

9. In an elastic fluid turbine, at least one rotor blade row comprising rotor blades and at least one guiding blade row, comprising guide blades, each blade of both rows having an entrance edge shar at one end and changing gradually radia y and-outwardly of the turbine into a rounded edge part, having its greatest rounding at the point farthest out along a radial line.-

10. A blade for an elastic Huid turbine having an entrance edge partly rounded and partly sharp, and formed so that the entrance edge angle increases towards the end of the blade which is outward with respect to the turbine.

11. In an elastic Huid turbine, a blade row comprising blades, each of which has an entrance edge partly rounded and partlysharp, and changing gradually from the sharp portion to the rounded portion, so that the entrance edgeY angle' increases gradually with the increased rounding. v 12. yIn a fluid pressure turbine having a stator and a rotor, a blade having an en\ trance edge, at least part of which isl rounded in transverse section and which differs at least in `part from a straight line radial to the axis of said rotor.

13. In a Yfluid pressureturbine having a stator and a rotor, a blade having -an entrance edge including a portion partly rounded in transverse section vand a sharp remaining portion, said` entrance edge differing at least in part along such curved edge section from a'straight line radial to the rotor axis.

14. Ina fluid pressure turbine, a stator, a rotor, and blading including blades at the low pressure end of the turbine, each of such blades having an entrance edge, at least part of which is rounded in transverse section and which differs at least in part from a straight lne'radial to the axis of said rotor. In testimon whereof I aix my signature 4 15. In a fluid pressure turbine, a stator, a in presence o two witnesses.V rotor, and blading including blades at the low-pressure end of the turbine, each of such FRANZ LSEL" 5 blades having an entranceedge, atleast part Witnesses:

of which is rounded in transverse section Onm DREMAN,

'and the remaining portion is sharp PARIL LEOPELD. 

